

#include <queue>
#include <memory>
#include <mutex>
#include <condition_variable>

template <typename T>
class threadsafe_queue
{
private:
    mutable std::mutex mut;
    std::queue<T> data_queue;
    std::condition_variable data_cond;

public:
    threadsafe_queue() {}
    threadsafe_queue(threadsafe_queue const &other)
    {

        std::lock_guard<std::mutex> lk(other.mut);

        data_queue = other.data_queue;
    }
    void push(T new_value) //⼊队操作
    {

        std::lock_guard<std::mutex> lk(mut);

        data_queue.push(new_value);

        data_cond.notify_one();
    }

    void wait_and_pop(T &value) //直到有元素可以删除为⽌
    {
        std::unique_lock<std::mutex> lk(mut);

        data_cond.wait(lk, [this]
                       { return !data_queue.empty(); });

        value = data_queue.front();

        data_queue.pop();
    }

    std::shared_ptr<T> wait_and_pop()
    {

        std::unique_lock<std::mutex> lk(mut);

        data_cond.wait(lk, [this]
                       { return !data_queue.empty(); });

        std::shared_ptr<T> res(std::make_shared<T>(data_queue.front()));

        data_queue.pop();

        return res;
    }

    bool try_pop(T &value) //不管有没有队⾸元素直接返回
    {

        std::lock_guard<std::mutex> lk(mut);

        if (data_queue.empty())

            returnfalse;

        value = data_queue.front();

        data_queue.pop();

        returntrue;
    }

    std::shared_ptr<T> try_pop()
    {

        std::lock_guard<std::mutex> lk(mut);

        if (data_queue.empty())

            return std::shared_ptr<T>();

        std::shared_ptr<T> res(std::make_shared<T>(data_queue.front()));

        data_queue.pop();

        return res;
    }

    bool empty() const
    {

        std::lock_guard<std::mutex> lk(mut);

        return data_queue.empty();
    }
};



int main ()
{
    
    return 1;
}